Question

Perbandingan rusuk balok adalah 2:3:5. volume balok 1920 cm3.berapa seluruh luas permukaan balok?

Answer 1

Volum balok = 1920
2a x 3a x 5a = 1920
           30a³ = 1920
               a³ = 1920/30
               a³ = 64
               a = ∛64
               a = 4
panjang = 2 x 4
             = 8
lebar = 3 x 4
        = 12
tinggi = 5 x 4
         = 20
Lp = 2 ( pxl + pxt + lxt )
     = 2 ( 8x12 + 8x20 + 12x20)
     = 2 ( 96 + 160 + 240)
     = 2 (496)
     = 992 cm²


jawabannya adalah 992cm²

Answer 2

P = 2/10 X 1920
= 384 cm
l = 3/10 X 1920
= 576
t = 5/10 X 192
= 690

V = p X l X t
1920 = 2x X 3x X 5x
1920 = 30x³
x³ = 1920/30
x³ = 64
x = ∛64
x = 4

p = 2x = 2X4 = 8 cm
l = 3x = 3X4 = 12 cm
t = 5x = 5X4 = 20 cm

L = 2(pXl)+2(pXt)+2(lXt)
= 2(8X12)+2(8X20)+2(12X20)
= 2(96)+2(160)+2(240)
= 192+320+480
= 992 cm²

Maaf, kalau ada yang salah.